Hey everyone, I'm new to this site looking for a little info.  For those of you that use a water/cement mix to slick your lines, how thick is your mixture?  (water/cement ratio)

A little background for me.....I work at an underground mine which requires a large amount of concrete(~6000-7000yds/month.......every month).  Our batch plant on surface loads trucks which dump into a 500m vertical borehole of 8" diameter(has it's own issues) into a stationary schwing pump which then pumps throughout the mine, sometimes distances of 300m.  We are constrained by infrastructure which means that we have LOTS of bends(90's, 120's, numerous 45's and 22's....I'm working on taking out those bends and reducing the pressure losses) and lots of elevation changes.  One issue we have is frequently plugging up on our first batch of concrete which I'm thinking is a slicking issue.  Currently our cement/water mix is so thin it's like water...even putting a pig ahead of the mix doesn't help since we still plug as I think the front end of the concrete is getting washed out and rock jamming.   Our slumps are ~9-10" just so it safely makes it down the slickline, out of the boot and into our pump.  5" steel lines everywhere, except through the rock which is just steel drill pipe.  Just to ensure the lines don't plug I have the guys break lines and drain off all our grout before the concrete hits it.....usually that works.

Just looking for any info you guys think might help. Thanks

I mix my cement / water mixture to pancake batter consistancy

I want my grout wet. almost soupy you will only need to fill the hopper and that should be plenty . give it some strokes before you drop the mud. but don't drop the grout unless the mud is there waiting. or you will be in trouble.

Bentonite,but you cant get it in the forms,slabs,walls.55gal drum works.And it;s cheap,$3.00 for 90 lbs

Funny I just have a lot of experiance with this. You primer is obviously to thin. Hard to describe but something like yoghurt or just a bit stiffer is perfect. Ony cement and water you shoud be able to prime endless lines.

Our ''water-cement'' number is 44-45 We also use a load of retarder. Like 10 liters per m3.

Is the line going down hill? that first put a soft ball in the pipes. Than 20 liters water and one more soft ball. Also a bit water in the hoper and 1 m3 of this cement water mix. That way the first bit of the mix gets very wet but the rest will stay stiff so you don't get the seperation. Can not fail. Send me a P.M. if you want. I have a video of the mix coming out of the truck so you can see how it should look like.

BTW You are in a mine? Did you ever hear about the brand SARAKA? The make very interesting concrete trucks for mining industry..

I've primed a ton of line in my day and I never stuck a softball or any kind of ball in my line. that just sounds like a potential problem. I'm sure it worked before but if you jam up with that in the line you are in for a miserable day

Only a ball ahead if the line is going down hill!!

that sounds like the jansen mine.  dipstick pretty much covered it.  ball water ball grout will help if you have to stop during ur prime because of the auger down the shaft.  

id mix in some extra grout in the first hopper.  imo, you can never have too much priming grout.  they have power buggies down there to catch the first m3 of concrete to dispose of.  better and cheaper than a plug!

Thanks guys, that info helps. 

We got lines going uphill, downhill, vertical drops through rock so plugging in a wall where you can't break a line sometimes makes for tense moments.   On some pours with long drops we will wear out the elbows after 400yds. We stay away from balls on those pours through walls because if it happens to jam up in the wall then we have no way to wash out from the bottom end.  I only have them use a pig on the open line pours just to ensure full pipe coverage.  

Our mixes vary.....our high strength mix had about 800lbs cement with closer to 5050 rock sand by weight, our weaker mixes around 650lbs cement one mix with 5050 rock and sand the other 75 % sand and 25% rock.   Run super p's and retarder and occasionally a viscosity modifier. 

Once she gets going it'll pump all day unless the guys on surface send a bad batch down.  Seems most of our issues are with the first batch.  

Haven't heard of those underground concrete trucks.   Is like to get ours replaced so I might look into them. 

Thanks again for all the info though.   I figured the guys that are doing this for a living would be able to help. 

Oh and not Jansen.......trickier mining than that ;)

I see their site is not very complete. Thats maybe because they don't just deliver standard products like the big guys do. They often build custom made equipment. If you are realy interested you could contact them. Ask Tapani Holming if he can build you a truck that fits in your mine and who knows what the answer is and how much it will cost  Ill get a hold of that video soon.. 

Cool crazzy_miner.  

good luck play safe

I usually send the first half yard of VERY soupy grout (with very little sand if any in grout mix)  and mix the next half yard of VERY soupy grout with your regular mix as its going into pump.  Pump nice and slow and slow and you should eventually get 1/2 yard grout, half yard of grout and concrete mix, and shazzam you're pumping the real sh#$!  Has worked every time for me, even with over 700 ft of line reduced down as small as 2.5 in rubber.  Good luck with it and pump on.  Sounds like a pretty cool job.